JP3852242B2 - Incandescent lamp for heat source - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an incandescent lamp, and more particularly to an incandescent lamp that is lit with the coil axis of a filament oriented vertically.
[0002]
[Prior art]
In a generally used one-end sealed incandescent lamp, for example, inside a cylindrical glass bulb, a coiled filament is connected to a supporter that also serves as an internal lead wire at both ends of the filament, The valve shaft and the coil shaft are held and arranged so as to coincide with each other.
When such an incandescent lamp is used by being lit vertically, the coil of the filament hangs down with the lighting time, and the coil extends downward to be deformed.
[0003]
[Problems to be solved by the invention]
In the incandescent lamp as described above, since the coil axis of the filament is vertical, a load having a magnitude equal to the coil's own weight is applied to the filament. The load generated by the dead weight gradually increases as it goes upward from the lower end of the filament, and becomes maximum at the upper end of the filament. For this reason, since the load applied to the filament at the lower end of the filament is small, the coil does not easily hang down and is not easily deformed.However, the load increases toward the upper end, so that the coil droops significantly and the coil stretches. This increases with this.
[0004]
On the other hand, since the filament of the incandescent lamp as described above is fixed with the upper end and the lower end connected to the supporter, the filament length and the number of turns of the coil do not change. When the drooping occurs, the pitch of the coils positioned below the pitch gradually decreases, and the coils adjacent to each other in the upper and lower sides eventually come into contact with each other. When this happens, a situation such as short-circuiting or fusing of the filament is caused, and the lamp is not lit, so that the lamp life is shortened.
In particular, in the case of an incandescent lamp that is used at a high temperature such that the filament temperature is, for example, 2600 ° C. or higher and is turned on and off in a short time and pulsed, the drooping of the coil is remarkable and the lamp life is extremely short. There was a problem.
[0005]
In view of the above problem, for example, a supporter can be attached not only at the upper and lower ends of the filament but also along the longitudinal direction of the filament to prevent the coils from contacting each other. However, according to such a method, the structure of the filament part becomes complicated, and the productivity is extremely deteriorated.
Furthermore, when using an incandescent lamp as a heat source, especially when the filament length of the incandescent lamp is approximately the same as the filament length and the coil diameter, the heat efficiency of the lamp is reduced. As few as possible is preferable.
[0006]
Therefore, an object of the present invention is to provide an incandescent lamp having a long service life by preventing the lamp from being turned off and shortening its life due to the drooping of the coil with a simple configuration.
[0007]
[Means for Solving the Problems]
Therefore, the invention according to claim 1 is a pair of supporters in which a filament composed of a double coil is accommodated in a valve, and the filament axis is oriented vertically and the upper and lower ends of the filament also serve as internal leads. It is connected and fixed so that the filament length does not change, and the coil pitch of the filament is gradually widened downward .
[0008]
According to the second aspect of the present invention, a coil-shaped filament is accommodated in the valve, and the filament is connected to a pair of supporters in which the axis of the filament is vertical and the upper and lower ends also serve as internal leads. The coil length is fixed so as not to change, and the coil is conical or frustoconical, and is arranged with one end having a small coil diameter facing upward.
[0009]
[Action]
[1]
Usually, as described above, the coil droops significantly above the filament, and when the coil extends and hangs down, the coil pitch is narrowed below the filament, and eventually the coil comes into contact.
Therefore, in the invention according to claim 1, without changing the filament length or the number of turns of the coil, the upper coil is wound more densely than the coil below the coil, and the deformation of the coil is anticipated in advance. The coil pitch above the filament is narrower than the lower side, and the lower pitch of the filament is wound wide.
With such a configuration, even if the coil hangs down and the coil pitch on the lower side becomes narrow, it takes a considerable time until the coils come into contact with each other. The fusing can be prevented. As a result, non-lighting of the lamp can be prevented and the life of the lamp can be extended.
[0010]
[2]
As the coil diameter decreases, the shear stress applied to the coil decreases with respect to the load in the axial direction of the coil, and thus the resistance against the load applied to the coil, that is, the droop resistance increases.
Therefore, according to the second aspect of the present invention, the sag resistance of the coil is increased by gradually decreasing the coil diameter as the load increases from the lower end to the upper end of the filament. Drooping can be effectively suppressed.
And since it becomes difficult to produce the deformation | transformation by drooping of a coil also above a filament, it can prevent that a coil pitch becomes narrow below a filament, and it becomes possible to avoid contact between coils. As a result, filament short-circuiting and fusing can be prevented, lamp non-lighting can be prevented, and the lamp life can be extended.
[0011]
DETAILED DESCRIPTION OF THE INVENTION
FIG. 1 shows an incandescent lamp according to the first embodiment of the present invention. In the incandescent lamp 10, for example, a filament 20 made of a double coil is disposed inside a glass bulb 11, filled with an inert gas containing a halogen substance, and a sealing portion 12 is formed at one end of the bulb 11. This is a so-called one-end sealed halogen lamp. The incandescent lamp 10 is installed with the tube axis of the bulb 11 in a substantially vertical direction, and is vertically lit with the sealing portion 12 facing upward as shown in FIG.
The supporters 30 and 30 ′ joined to the upper end and the lower end of the filament 20 are connected to molybdenum foils 31 and 31 ′ embedded in the sealing part 12, and the molybdenum foils 31 and 31 ′ are connected to the valve 11. It is connected to external lead rods 32 and 32 'protruding outward. The supporters 30 and 30 ′ hold the filament 20 and also have a power feeding mechanism for the filament 20, and also serve as internal leads.
[0012]
The coil 21 constituting the filament 20 is, for example, a coil 21 in which strands are wound twice. First, a tungsten wire having a strand diameter of 0.22 is wound at a constant pitch of 0.98 mm in diameter. Thus, a primary coil was produced, and this primary coil was then wound twice with a coil diameter R of 4.8 mm while changing the pitch in the direction of the winding axis of the coil. For example, the coil 21 is used for 6 to 7 turns in terms of the number of turns.
[0013]
Here, the enlarged view for explanation of the filament 20 portion is shown in FIG. Here, for the sake of simplicity, description will be made with reference to the drawing of a single coil.
The filament 20 is wound with the pitch of the coil 21 different between the upper side and the lower side, and the upper pitch is narrower than the lower pitch. As an example, the pitch p ₁ from the winding start point (0) of the coil 21 to the point (1) wound one turn from the (0) point is 0.98 mm, and the pitch p ₂ below it is 1. The pitch p ₃ is 16 mm, and the lower pitch p ₃ is 1.34 mm, and the pitch becomes wider every time the coil 21 is wound.
[0014]
In the case of a conventional incandescent lamp, when the coil 21 hangs down, at the upper end of the filament 20, the coil 21 expands with the lighting time and the pitch widens, and the pitch gradually narrows as it goes downward. However, according to the first embodiment, since the pitch gradually increases downward corresponding to the deformation of the coil 21, it is adjacent to the upper and lower sides in the longitudinal direction of the filament 20. Contact between the coils 21 can be avoided, and short-circuiting and fusing of the filament 20 can be prevented.
As a result, lamp non-lighting can be prevented and the lamp life can be extended.
[0015]
Next, an embodiment of the invention of claim 2 will be described.
FIG. 3 shows a second embodiment, and is a view showing a main part of the incandescent lamp according to the invention of claim 2. FIG. 3 (a) is a front view of the filament 20 as viewed from above, and FIG. ) Is a front view of the filament 20 as viewed from the side.
The filament 20 is a coil 21 that is produced by winding a tungsten wire while sequentially changing the diameter in the coil axis direction, and has a conical (or also called a truncated cone) appearance.
[0016]
The filament 20 is, for example, a coil 21 having a constant pitch angle, and the radius r (mm) of the coil at a point (4) below the filament 20 in the figure is, for example, r ₄ = 2.33. Each time, the radius becomes smaller. Specifically, the diameter of the coil 21 gradually decreases as r ₃ = 2.18, r ₂ = 2.02,. ₀ = 1.70.
[0017]
Although not shown, the filament 20 has a pair of supporters attached to the upper end 22 and the lower end 23 of the coil 21, with the conical apex 24 of the coil 21 on top and the coil axis in a substantially vertical orientation, so that the coil diameter is small. One end, that is, the upper end 22 is arranged on the upper side, and the other end having a large coil diameter, that is, the lower end 23 is arranged on the lower side.
The description of the overall structure of the incandescent lamp according to the second embodiment is omitted, but other configurations related to the incandescent lamp, excluding the filament 20, such as a bulb, an enclosed gas, or a supporter. The configuration is the same as that of the first embodiment described above.
[0018]
When the above configuration, that is, when the coil axis is vertical and the diameter of the coil on the upper side is smaller than that on the lower side, the drooping of the coil can be suitably suppressed above the filament. That is, since the drooping resistance can be increased corresponding to the load applied to each part of the coil, it is difficult for the coil to be deformed due to the drooping of the coil, and the coil pitch is hardly narrowed even under the filament.
Since the contact between the coils of the filament can be avoided, it is possible to prevent a short circuit and a fusing associated with the contact of the filament.
As a result, non-lighting of the lamp can be prevented and the life of the lamp can be extended.
[0019]
In the invention according to claim 2, since it is sufficient that the appearance of the filament is a cone (or a truncated cone), the coil diameter does not have to be displaced at a constant rate in the coil axis direction of the filament. .
Further, when the filament is viewed from above, it is not limited to the one in which a gap is formed between the coils as shown in FIG. 3A. For example, the gap may not be formed. It may be something that appears to overlap.
[0020]
By the way, the invention described in claim 2 may be variously modified as long as the diameter of the coil above the filament when the lamp is used is small. For example, the coil pitch (p _{1 to} p ₄ in FIG. 3B) may be displaced in the coil axis direction, and can be combined with the invention according to claim 1. That is, it may be a coil having a conical appearance as shown in FIG. 3B, and the coil pitch (p _{1 to} p ₄ ) may increase from the upper side to the lower side of the filament.
[0021]
When the inventions according to claims 1 and 2 are combined, a further improvement can be expected with respect to a longer lamp life. With such a configuration, in addition to the effect of increasing the drooping resistance against the load of the coil by reducing the coil diameter above the filament compared to the lower side, the coil with the long-term use of the lamp Even if the drooping of the coil occurs and the coil pitch on the lower side becomes narrower than that of an unused lamp, it is possible to avoid coil contact for a long period of time by widening the coil pitch in that portion in advance. It is possible to prevent problems such as short-circuiting of the filament and to prevent the lamp from being turned off.
As a result, a tremendous effect can be obtained for extending the lamp life.
[0022]
The first and second embodiments described above can be appropriately changed in any case, and the numerical values are not limited to those described above, and other configurations can be changed. For example, the present invention can be carried out when the filament coil is a single coil or a double coil.
[0023]
(Example)
In the first aspect of the present invention, the displacement of the coil pitch can be easily determined by applying the following equation.
・ P _n = a (2πn) ^m-1
(Where a is an arbitrary constant, 1 <m ≦ 3)
Hereinafter, this embodiment will be described.
FIG. 4 shows the relationship between the pitch P _n and the radial displacement θ from the starting point (0) at an arbitrary point (N) n turns around the coil from the winding starting point (0) of the coil. FIG. Note that the pitch P _n at the point (N) represents the pitch between the point (N−1) and the point (N).
When moving on the coil by 1 pitch, in the radial direction, it moves around the coil and is displaced by 2π. Therefore, the radial displacement from the starting point (0) at the point (N) is generally expressed as θ _n = 2πn. it can.
Here, an arbitrary point on the coil is represented by coordinates. First, assuming that the point on the circle drawn by the coil radius (r) is X, Y, the coil axis is the Z axis, and the longitudinal position is Z,
X = r cos θ, Y = rsin θ, Z = kθ ^m
Respectively. (K and m are arbitrary constants.)
[0024]
Therefore, the pitch between the two points can be derived from the above equation Z, and the radial displacement θ _{n at the} point (N) can be written using n, and between the points (N−1) and (N) The pitch P _n can be expressed by the following equation using the number of turns _n of the coil.
・ P _n = a (2πn) ^m-1 (a and m are arbitrary constants)
In this equation, when m = 1, P _n = a (constant), and in this case, the coil pitch is constant.
Subsequently, when the value of m exceeds 1, the pitch increases from the upper end to the lower end of the coil. Therefore, the invention according to claim 1 can be suitably used within a range of 1 <m. For example, if m = 2, the pitch is P _n = 2πan and is represented by a linear function of the number of turns n of the coil, and the pitch increases from the upper end to the lower end of the coil by the same width. When m = 3, the pitch increases in a quadratic function with respect to the number of turns.
[0025]
By the way, if the value of m is too large, the specs of incandescent lamps that are generally used will be deviated, and the above formula cannot be applied. The inventors have analyzed the value of m that satisfies the specifications of the conventional lamp and can apply the above formula. When m = 3, it is sufficient to set the constant a small. It turned out to be possible. Therefore, it is understood that the present invention can be implemented when m is 3 or less.
[0026]
As a result, the following equation is derived.
P _n = a (2πn) ^m-1 (where a is an arbitrary constant, 1 <m ≦ 3)
Furthermore, it has also been found that the widest pitch p _max is optimal in the range of p _min <p _max ≦ 3 × p _min with _respect to the narrowest pitch p _min .
[0027]
In the first aspect of the present invention, when the rate at which the coil pitch is narrowed is generally large at the lower end of the coil and becomes smaller upward, the coil pitch is gradually displaced while satisfying the above equation. The pitch according to the amount of deformation of the coil can be easily obtained.
As a result, contact between the coils can be avoided over the entire length of the filament, and a long-life lamp can be obtained.
[0028]
As described above, according to the present invention, in an incandescent lamp for a heat source in which a filament made of a coil is accommodated in a bulb and the filament axis is positioned in a vertical direction and is lit, Even if such deformation occurs, it is possible to prevent the coils from coming into contact with each other with a simple configuration, prevent filament short-circuiting or fusing, and provide a long-life incandescent lamp for a heat source .
[Brief description of the drawings]
1 is an enlarged view of the filament shown in FIG. 1. FIG. 3A is a front view of the filament as viewed from above. FIG. Front view seen from the side [Fig. 4] Diagram showing the relationship between radial displacement θ and pitch _Pn [Explanation of symbols]
DESCRIPTION OF SYMBOLS 10 Incandescent lamp 11 Bulb 12 Sealing part 20 Filament 21 Coil 22 Upper end 23 Lower end 24 Top part 30, 30 'Supporter 31, 31' Molybdenum foil 32, 32 'External lead rod

Claims (2)

A filament consisting of a double coil is housed in the bulb, and the filament is fixed so that the filament length does not change by connecting the filament axis vertically to a pair of supporters whose upper and lower ends also serve as internal leads. has been made, the heat source for incandescent lamps, wherein the coil pitch of the filaments becomes gradually wider downwardly. A coiled filament is accommodated in the bulb, and the filament is fixed so that the filament length does not change by connecting the filament axis vertically to a pair of supporters whose upper and lower ends also serve as internal leads. The incandescent lamp for a heat source is characterized in that the coil is conical or frustoconical and is arranged with one end having a small coil diameter facing upward.

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